I have been using Wally for Wallpaper rotation. It is a QT4 application that
curiously works well on GNOME, but not on KDE 4. They are working on it. It
displays wallpaper from html webpages online and supports: Flicker, Buzznet,
PhotoBucket, ipernity, Pikeo, Picasa, and Yahoo.

Review:
webupd8.blogspot.com/.../...wallpaper-changer.html
Source: www.becrux.com/index.php?page=projects&name=wally